Reversing switch for tap changing transformer regulator



1965 P. B. MACELLONI 3,164,710

REVERSING SWITCH FOR TAP CHANGING TRANSFORMER REGULATOR Filed April 12,1962 1%1'0 B Mace/hm; y fiM/v :47;

United States Patent Piez'o B. Maceilorni, Pittsiield, Mass, assignor toGeneral Electric Qonipany, a corporation of New York Filed Apr. 12,1962, Ser. No. 187,862 Claims. (Cl. ace-17c This invention relates toelectric switches and more particularly to improvements in reversingswitches for use in tap changing type transformer regulators.

Heretofore switches of this type have had considerable friction and theyhave caused undue strain on and in some cases actual stalling of theoperating mechanism of the regulator.

In accordance with this invention there is provided a novel and simpleswitch which assures very firm eventual contact engagement when moved ineither direction from a neutral position in which there is practicallyno initial friction and reduced final friction with the friction duringthe initial contact engagement occurring at a location where theopposing moment arms are small so as to provide a large mechanicaladvantage during this period of operation of the switch.

An object of the invention is to provide a new and improved electricswitch.

Another object of the invention is to provide a new and improvedreversing switch for tap changing type transformer regulators.

The invention will be better understood from the following descriptiontaken in connection with the accompanying drawing and its scope will bepointed out in the appended claims.

In the drawing, FIG. 1 is :a perspective view of a preferred embodimentof the invention and FIG. 2 is an elementary circuit diagram of how itmay be connected to a transformer tap changing type regulator.

Referring now to the drawing and more particularly to FIG. 1, there isshown therein a contact 1 and a contact 2 spaced therefrom along the arcof a circle having its center on the axis 3 of a sector shaped commoncontact 4. Actually the sector shaped common contact 4 consists of acontact 5 and a contact 6 which may, if desired, be separate contactsbut which are preferablyshown permanently connected together.Cooperatlng with the four contacts 1, 2, 5, and 6 are a pair of bridgingcontact fingers 7. The contact 5 is generally radially aligned with thecontact 1 and the contact 6 is generally radially aligned with thecontact 2. Furthermore, it is immaterial whether the bridging contacts 7are the movable contacts and the other contacts are the stationarycontacts or vice versa, the only essential thing being that there berelative movement. However, I prefer the former arrangement in which thebridging contacts '77 are movable and the radially aligned contact pairsl5 and 2-6 are fixed contacts. It will be noted that the contacts 1, 2,5 and 6 have a thickness a between flat sides and that they are allmounted in generally coplanar relation with their fiat sides parallel totheir common plane which is generally perpendicular to the common axis3. It will also be noted that the angular displacement between thefacing edges of the radially outermost fixed contacts 1 and 2 is lessthan the angular displacement between the facing edges of the radiallyinnermost fixed contacts 5 and 6.

3,lfi4,7lil Patented Jan. 5, 1965 Furthermore, while all of those facingedges are somewhat chamfered or beveled, this is much more pronounced onthe radially innermost fixed contacts 5 and 6 which preferably haverather sharp edged Wedge-shaped facing edges.

The elongated bridging contact fingers 7 are carried by a frame 8mounted for rotation in the sector 4 about the axis 3. This frame isshown as having a pair of parallel radially extending arms 9 betweenwhich extend a pair of parallel radially spaced tie rods ill on whichthe contact fingers 7 are mounted by means of suitable holes locatedtherein. Coiled compression springs 11 mounted on the rods 10 betweenthe contact fingers 7 and the arms 9 serve to urge or bias the contactfingers 7 toward each other. However, they are held apart by tubularspacers 12 and 13 mounted respectively on the rods ll) between thecontact fingers 7. The spacer 12 is longer than the spawr 13 but shorterthan the thickness of the contacts 1 and 2. Actually only one arm 9 isnecessary, in which case the springs 11 are retained onthe outer ends ofrods 10 in any suitable manner.

The switch is shown in FIG. 1 in its so-called neutral position in whichthe bridging contact fingers 7 are between the respective pairs of fixedcontacts 1-5 and 246 but out of engagement therewith. It now the frame 8is rotated in either direction from this neutral position, the firstthing to be noted is that the radially outermost ends of the contactfingers 7 will come into overlying relation with opposite sides ofeither contact 1 or contact 2, depending on the direction of rotation ofthe frame, without touching them before any contact is made be tween theradially innermost ends of the contact fingers 7 and the radiallyinnermost fixed contacts 5 and 6. This is illustrated by the clockwiserotated dashed line position of fingers 7 and is because of the smallerangular distance between the facing edges of the contacts 1 and 2 thanbetween the facing edges of the contacts 5 and 6. When the inner ends ofthe contact fingers 7 first contact either the fixed contact 5 or thefixed contact 6 there will be a wedging action caused by the pronouncedwedge shape of the facing edge of the contact 5 or contact 6. At thispoint for the first time there will be introduced noticeable reactiveimpact and frictional forces opposing the rotation of the frame 8.However, because these forces are located near the axis 3 their momentarms will be comparatively small and they thus will not have apronounced restraining efiect on the continuing rotary movement of theframe 8. As this rotary motion continues the wedging action will spreadthe radially inner ends of the contact fingers 7, which will pivot aboutpoints 14 where the ends of the spacer 12 touch the contact fingers 7.This will, of course, move the outer ends of the contact fingers towardthe sides of the contacts 1 or 2 as the case may be. As this actioncontinues the outer ends of the contact fingers 7 will engage the sidesof the contact 1 or the contact 2 as the case may be and with stillfurther rotary movement the pivot points of the fingers 7 will now bemoved further outwardly to the points of contact between fingers 7 andthe sides of contace 1 or contact 2 as the case may be so that when theframe 8 reaches the limit of its travel in either direction the fullforce of the compression springs 11 will be exerted to pinch the contactpairs 1-5 or 26 between the contact fingers 7. This in turn is becausethe length of the spacer 12 is less than the thickness of the contacts 1and 2.

a 3 This position is illustrated by the counter-clockwise rotated dashedline position of the fingers 7.

FIG. 2 shows how the switch may be connected as a reversing switch for amultitap series winding 15 of an autotransformer type voltage regulator16. As shown the series winding 15 is provided with a tap changing ratioadjuster switch 17 while contacts 1 and 2 of the reversing switch areconnected to the terminals of the series winding 15 and the commoncontact 4 of the reversing switch is connected to one of the lines ofthe circuit for the regulator 16. In general, the purpose of thereversing switch is to double the range of regulation of the regulator16 by causing the series winding to be connected for one polarity of theseries winding 15 throughout the complete range of the operation of thetap changer 17 while in the other position of the reversing switch thepolarity of the series winding 15 is reversed so that the tap changer 17may gothrough its complete range of operation, again thus providingselective voltage raising and lowering or voltage buck and boost actionas the tap changer 17 goes through its range of operation.

While there has been shown and described a particular embodiment of theinvention, it will be obvious to those skilled in the art that changesand modifications may be made without departing from the invention, andtherefore itis intended by the appended claims to cover all such changesand modifications as fall within the true spirit and scope of theinvention.

What I claim as new and desire to secure by Letters;

said pair of contacts for causing selective bridging engagement anddisengagement between said bridging contact and said pair of contacts,means mounting said bridging contact to cause engagement of saidbridging contact first with only one of said pair of contacts with saidbridge contact and the other of said pair of contacts being in spacedapart overlying relation and means cooperating with said mounting meansfor causing relative movement between said bridging contact and saidpair of contacts in a plane perpendicular to said givenplane for nextcaus ing said bridging contact to engage said other of said pair ofcontacts.

2. In an electric switch, a pair of coplanar flat sided spaced apartcontacts, a bridging contact, means forcausing relative rotary movementin a given plane about a common axis between said bridging contact andsaid pair of fiat sided contacts for causing selective bridgingengagement and disengagement between said bridging contact and the sidesof said pair of contacts, means mounting said bridging contact to causeengagement of said bridging contact first with a radially innermost oneonly of said pair of contacts with said bridging contact and theradially outermost other of said pair of contacts in spaced apartoverlying relation, and means cooperating with said mounting means forcausing relative movement between said bridging contact and said pair ofcontacts in a plane perpendicular to said given plane for nextcausing'said bridging contact to engage a side of the radially outermostof said pair of contacts.

3. In an electric switch, four generally flat sided contacts mounted incoplanar relationship, said contacts being grouped in two pairs alignedalong different radii from a common center, the radial location ofthecon tacts of each pair being the same, a pair of elongated bridgingcontacts extending in a radial direction'from said common center meansfor moving said bridging contacts around said common center from aposition in which they respectively bridgingly engage opposite faces ofone pair of fiat sided contacts through a neutral position in which theyare out of contact with said flat sided contacts to a position wherethey respectively contact opposite faces of other pair of flat sidedcontacts, means for biasing said bridging contacts toward each other forcausing their opposite ends to pinch each pair of flat sided contacts,and spacer means between said bridging contacts for causing their endsnearest said common center to be closer together than the thickness ofthe two radially innermost fiat sided contacts and their ends farthestfrom said common center to be farther apart than the thickness of thetwo radially outermost flat sided contacts when said bridging contactsare in said neutral position, the angular separation of the facing edgesof the radially outermost flat sided contacts being less than theangular separation of the facing edges of the radially innermostcontacts whereby when said bridging contacts are moved from said neutralposition their outer ends are spaced from but overlie the radiallyoutermost flat sided contacts when their inner ends first contact theedges of the radially innermost fiat sided contacts, said edges of saidradially innermost flat sided contacts being wedge shaped for enteringbetween the inner edge of said bridging contacts so as to cause theouter ends of said bridging contacts to move toward each other and pinchthe radially outermost contacts therebetween.

4. In an electric switch, four generally flat sided fixed contacts ofgenerally equal thickness mounted in a spaced relation with their fiatsides in parallel coplanar relation, said fixed contacts being groupedin two pairs in which each pair is aligned along different radii from acommon center, the radial location of the contacts of each pair alongtheir respective radii being the same, a pair of elongated fiat sidedbridging contacts extending in a radial direction from said commoncenter, means for moving said bridging contacts in union around a commoncenter in a position in which their flat sides respectively bridginglycontact opposite faces of one pair of flat-sided fixed contacts througha neutral position in which they are out of contact with said flat sidesfixed contacts to a position where they respectively bridgingly contactopposite faces of the other pair of flat sided fixed contacts, springmeans for biasing said bridging contacts toward each other for causingtheir opposite ends to pinch each pair of flat sided contacts and spacermeans between said bridging contacts for causing their ends nearest saidcommon center to be closer together than the thickness of the tworadially innermost flat sided fixed contacts and their ends farthestfrom said common center to be farther apart than the thickness of thetwo radially outermost flat sided fixed contacts when said bridgingcontacts are in said neutral po'sition,'the angular separation of thefacing edges of the radially outermost fiat sided fixed contacts beingless than'the angular separation of the facing edges of the radiallyinnermost fixed contacts whereby when said bridging contacts are movedfrom said neutral position their outer ends are spaced from but overliethe radially outermost flat sided fixed contacts when their inner endsfirst contact the edges of the radially innermost fiat sided fixedcontacts, said edges of said radially innermost flat sided fixedcontacts being wedge shaped for entering 1 between the inner ends ofsaid bridging contacts and spreading them apart so as to cause the outerends of said bridging contacts to move toward each other and pinch theradially outermost fixed contacts therebetween.

5. An electric switch comprising, in combination, a frame mounted forrotation about a fixed axis through equal angles from a neutralposition, two pairs of fixed contacts, each pair of fixed contacts beingaligned respectively on different radii from a point on said axis whichradii having angular displacement equal to the range of angular motionof said frame, the radially outermost cont-acts of each pair of fixedcontacts having the same radial distance from said axis and the radiallyinnermost contacts of each pair of fixed contacts having the same radialdistance from said axis, said frame having a pair of axially spaced armsextending radially from said axis in the same direction, a pair ofparallel radially spaced Z3 tie rods joining said arms and so located asto pass between the contacts of each pair of fixed contacts when saidframe is rotated through said angles from its neutral position, a pairof bridging contact fingers loosely mounted on said rods, coiledcompression springs on said rods between said arms and said contactfingers, and a pair of tubular spacers on said rods between said contactfingers, the spacer on the radially outermost rod being longer than theother spacer but shorter than the axial distance between opposite sidesof said fixed contacts, the edges of the radially innermost of saidpairs of fixed contacts being beveled in a direction facing the innerends of said bridging contact fingers.

References Cited by the Examiner UNITED STATES PATENTS BERNARD A.GILHEANY, Primary Examiner.

0 ROBERT K. SCHAEFER, Examiner.

1. IN AN ELECTRIC SWITCH A PAIR OF SPACED APART CONTACTS, A BRIDGINGCONTACT, MEANS FOR CAUSING RELATIVE MOVEMENT AND DISENGAGEMENT OF SAIDBRIDGING CONTACT FIRST SAID PAIR OF CONTACTS FOR CAUSING SELECTIVEBRIDGING ENGAGEMENT AND DISENGAGEMENT BETWEEN SAID BRIDGING CONTACT ANDSAID PAIR OF CONTACTS, MEANS MOUNTING SAID BRIDGING CONTACT TO CAUSEENGAGEMENT OF SAID BRIDGING CONTACT FIRST WITH ONLY ONE OF SAID PAIR OFCONTACTS BEING IN CONTACT AND THE OTHER OF SAID PAIR OF CONTACTS BEINGIN SPACED APART OVERLYING RELATION AND MEANS COOPERATING WITH SAIDMOUNTING MEANS FOR CAUSING RELATIVE MOVEMENT BETWEEN SAID BRIDGINGCONTACT AND SAID PAIR OF CONTACTS IN A PLANE PERPENDICULAR TO SAID GIVENPLANE FOR NEXT CAUSING SAID BRIDGING CONTACT TO ENGAGE SAID OTHER OFSAID PAIR OF CONTACTS.